P0457 on Ford: How to Diagnose & Fix
Evaporative Emission System Leak Detected (Fuel Cap Loose/Off)
2 Ford models · 2 documented issues · $30-$300 repair
P0457 on Ford by model: symptoms, diagnosis and fix
The under-hood evaporative-emissions purge valve on 2010-2011 Fusion/Milan (2.5L DOHC and 3.0L) built on or before 3/4/2011 can stick open or leak, letting unmetered vapor into the intake. This lights the MIL and sets a cluster of EVAP and lean/fuel-trim codes, and can cause rough idle or hard starts. Ford covered the affected build range under safety recall 15V793 (Ford 15S34) because the faulty purge valve can cause abnormal fuel-tank pressure changes that may crack the tank and leak fuel.
Common Symptoms
- Check engine light on
- Rough idle or stalling
- Hard start after refueling
- Fuel smell
- Failed emissions test
How to Fix
Check by VIN whether recall 15V793 (Ford 15S34) is still open: dealers update the PCM, leak-test the canister purge valve, inspect the fuel tank for cracks, and replace the purge valve and tank as necessary free of charge. Confirm the purge valve holds vacuum and clicks when energized; replace the stuck/leaking purge valve (inexpensive part). Verify no cracked EVAP hoses, a properly sealing gas cap, and an intact charcoal canister before clearing codes. Smoke-test the EVAP system if large-leak codes persist.
Sources for this issue (1)
The EVAP canister purge valve sticks open, causing difficulty fueling (pump nozzle keeps clicking off), rough idle, and check engine light. Very common on the 1.6L engine.
Common Symptoms
- Gas pump nozzle clicks off repeatedly
- Rough idle after fueling
- Check engine light
- Fuel smell
How to Fix
Replace the canister purge valve (solenoid). Clear codes and verify repair. Check EVAP hoses for cracks.
Sources for this issue (2)
P0457 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0457 mean on a Ford?
P0457 stands for "Evaporative Emission System Leak Detected (Fuel Cap Loose/Off)." This code means the engine computer detected a large leak in the sealed fuel-vapor (EVAP) system, most often traced to a loose, missing, or poorly sealing gas cap. The EVAP system is supposed to trap gasoline vapors and burn them in the engine instead of releasing them into the air; a big leak lets those vapors escape. It is an emissions-only fault that will not hurt the engine, though it triggers the check-engine light and can cause a faint fuel smell. On Ford it is documented across 2 models: Fusion, Fiesta.
What are the most common causes of P0457?
The most common causes of P0457 are: Loose, missing, or improperly tightened fuel cap, Worn or cracked fuel cap seal/gasket, Damaged fuel filler neck or sealing surface, Cracked or disconnected EVAP hose, Stuck-open purge or vent valve, Faulty fuel cap that won't hold pressure, Leaking charcoal canister. The specific cause varies by vehicle.
How much does it cost to fix P0457 on a Ford?
Published repair estimates on Ford range from $30 to $300 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.